The UN agency on Thursday unearthed the technology at its Paris headquarters following a successful test in Bangladesh rural areas.

The Unesco in February 2004 provided 14 families, who live in rural areas where groundwater has arsenic levels up to 0.5 milligrams per litre, with such filters.

"After more than 18 months of daily use, 12 of them are still producing arsenic-free water without requiring replacement of the sand absorbent," the Unesco statement said.

The Unesco will distribute additional 1,000 filters in the arsenic contaminated areas, where according to the World Health Organization (WHO), arsenic problem affects 30 million people, the statement added.

The technology of the filter is based on arsenic absorption with iron oxide-coated sand. It is easy to use, requires no power and can be produced locally, the statement said.

A family filter is able to produce 100 litres of arsenic-free water a day, enough to meet the demands of 20 people, it added.

"We found that this material, coated with iron oxides, is an excellent absorbent for removing arsenic from water. It is free of charge and consequently the technology based on its use is cheap, simple and ecologically sound," said Branislav Petrusevski, director of Unesco-IHE.

The Unesco, referring to the WHO estimates, said arsenic levels in the groundwater in Bangladesh are as high as 1.8 milligrams per litre, which crosses the healthy maximum of arsenic in water at 0.01 milligrams per litre.

The technology will help save tens of millions of lives around the globe, the statement added.

Moreover, the UN agency has developed a simple and cheap regeneration procedure for exhausted adsorbent for centralised arsenic removal applications. The technology, destined for water supply companies, is now being tested in Greece and Hungary.